Single surface grills are widely used in most restaurants for cooking a wide variety of food products. Many fast food restaurant menu items require cooking on both sides, and such restaurants have found it advantageous to cook both sides at the same time to expedite the cooking time. With a single surface grill it is necessary for the operator to turn, for example, hamburger patties over after they have been cooked on one side for cooking on the second side. This increases the amount of operator attention required for cooking these food products and also increases the cooking time.
Two-sided grills have been made with upper and lower cooking platens for cooking food products such as hamburger patties. Two-sided cooking grills reduce the overall cooking time and the amount of operator attention required for cooking the hamburger patties. However, there are a number of interrelated shortcomings in the two-sided cooking grills currently in use.
The upper cooking platen in two-sided grills used by commercial food service establishments are generally large enough to enable the operator to cook a number of individual hamburger patties or other items at the same time. The patties are preformed in several different nominal sizes and thicknesses and are commonly frozen for storage and transportation. The frozen patties are relatively rigid when initially placed on the lower cooking platen and if the upper platen rests only on the thickest patty or patties, even small differences in the thickness of the patties in the group being cooked can prevent or delay proper heat transmission from the upper platen to some of the thinner patties. This can result in uneven cooking of the patties. On the other hand, the patties typically soften and shrink or decrease in thickness as they thaw and cook. The weight of the upper cooking platen at this stage of the process can excessively compress the hamburger patties which can adversely affect the texture and appearance of the cooked patties.
Thus, two-sided grills present several special problems including: accommodating variations in initial thickness of the individual patties in the group being cooked; accommodating the decrease in thickness of the patties that occurs during cooking; preventing excessive compaction of the patties; and accommodating different groups of patties of nominally different thicknesses. In addition, in two-sided grills, there is the problem of moving the upper platen at the beginning and end of the cooking cycle. In order to facilitate timed cooking, the two-sided grill is desirably arranged to raise the upper platen at the end of a cooking cycle to stop cooking by the upper platen and enable removal of the cooked products from the lower platen.
Various two-sided grills have been made in which the upper cooking platen is mounted on a support arm for swinging movement about a horizontal axis between the lower cooking position and a raised position. On various two-sided grills the upper platen is counter-balanced with a gas spring to assist in the manual lifting of the platen at the completion of a timed cooking cycle. This greatly limits the amount of pressure that can be applied by the upper platen to the frozen patties when initially placed in the cooking position. Heat will not be quickly transmitted to the patties, and consequently, the patties will not achieve the desired amount of carmelization.
Other two-sided grills utilize an upper platen counterbalanced with heavy weights to automatically raise the platen and keep it in a raised position. These grills use electro-mechanical, pneumatic or hydraulic mechanisms to hold the platen in the cooking position and mechanical stops to regulate the spacing between the upper platen and the lower platen cooking surface. Some grills use multiple pins adjustably mounted throughout the cooking surface of the upper platen for engagement with the upper face of the lower platen as mechanical stops. These stop pins, however, limit the usable cooking area on the upper and lower platens and make it difficult to clean the upper platen. Grease and other debris generated by the cooking process tend to bake on the pins and impede their adjustment. Other grills use external cams mounted on shafts extending horizontally through the platen cover as mechanical stops. These are also difficult to clean and over time generate wear on the lower platen surface.
Still other arrangements include stop pins disposed inside the platen cover with the platen hanging or floating from the upper surfaces of these pins. The adjustment for the various product thickness settings is done by rotating a series of handles that protrude through the upper surface of the platen cover. Once again, the grease and other debris normally created by cooking hamburgers and other foods migrate down the handles, bake on the stop pins and impede their adjustment. In addition, the carbonized matter on the pins and hanging mechanism alters the distance between the platens, requiring regular realignment.
In each of these instances, the mechanical stops that regulate the spacing of the platens for the various products require that the stops be adjusted manually with each different product that is cooked. Even with such mechanical stops, when the food items are of even nominally different thicknesses, the upper platen will contact the thickest patty first. Only after the thickest patty has begun to shrink as it cooks will the platen contact the thinner patties. Because the mechanical stops are typically set for the finished product thickness, these stops will only be reached once the final, thinnest patties are contacted by the upper platen and cooked. Thus, such an arrangement provides very uneven cooking of the patties. This limitation can also be observed when individual patties have varying thicknesses across their surfaces. High spots will be overcooked or even burned, while portions having a lower profile will be undercooked. Individual patties, then, can have both burned and raw portions, providing an unacceptable product.
The present invention seeks to overcome these limitations by providing precise, controlled, two-sided cooking by means of an apparatus having a floating upper platen construction which allows for complete control of the degree of pressure the upper platen places on the food. The present invention also seeks to overcome these limitations by providing microprocessor control of both the upper platen operation and the entire cooking cycle. The upper platen according to the present invention is positioned substantially parallel to the patties and the lower platen prior to coming into contact with the patties. This optimizes cooked product quality and uniformity and minimizes operator involvement. The present invention also provides many additional advantages which shall become apparent as described below.